Engine makes clackiting/knocking sort of sound?

[ericem]

Hey guys, the car seemed to have always made this noise only when the engine is cold at idle. It is like a knocking sort of noise not a ticking like a injector or lifter per say. If I rev it, its smooth as silk though! Is this normal or what? Actually it is sort of like a clackity sort of noise hard to explain. I am running 10w-30 mobil 1 synthetic. Any ideas? I am talking about the 94 SS BTW!

What is wierd is when you get in the car you do not hear any knocking sort of sounds! extremely smooth. Hmm. My dad just always questions it and I figure I might as well make sure it is normal.

[Skruyd]

You might have a Hydraulic Lash Adjuster going out on you. One of the adjusters might be leaking out enough that when you are idling it forces the oil out, but when you rev it the oil might have enough pressure to keep it filled. If you can tell which side it is coming from. Try and bleed them out.

[ericem]

How important are the HLA's? Will they cause driveability issues? Like I said once it is warmed up pretty smooth, although there is a tiny studder at idle, then again after replacing my battery seems better.

[Skruyd]

How important are the HLA's? Will they cause driveability issues? Like I said once it is warmed up pretty smooth, although there is a tiny studder at idle, then again after replacing my battery seems better.

Yea they can cause driveability issues. If one or two are out you can drive but the engine will be weak. Or like me, all the intake HLA's on the driver side wasn't getting any oil and the engine will just die when I hit the gas. It's almost like having your timing off on one cam.

But the whole thing with the tiny studder at idle and it getting better after replacing the battery. Might be something different?

[ericem]

hmm interesting might explain why when i give more throttle the car does not go faster? Car is getting boost just doesnt always have good power. I basically need to remove the valve covers right i think i can find a write up. I probably need new ones though no point going to the trouble of removing them and not putting new ones.

Is it possible seafoam can clean them out ?

[Skruyd]

Some times it's worth it to take them out just to bleed them out. But yea, there is a write up on here on how to remove them. No need to replace them if they hold the oil though. They are about $30 a piece from the dealership, and 16 of them is a lot of money . Make sure you check the oil channels too in the rocker assembly. For some reason I had black crap blocking the channel in mine. Which made the intake HLA's not fill with oil.

[SLODRIVE]

You might try running 5W-30 oil as well. The thinner oil flows better when cold, and will fill the lifters better quite often.

[ericem]

I am confused though, why wouldn't they bleed themselves out? Basically the reason why there is no oil is because it is not flowing correctly right. Maybe seafoam will clear the passages which may be creating the issue. I am going to dump a bunch of seafoam and drive around for a good 10-20mins then do a oil change.

[Legacy777]

Yeah, if gunk/crud get in there, they can clog passages in the lifters.

[asc_up]

For what it's worth, I had the same problem and used 3/4 of a can of Sea Foam in the oil, drove it around for 30 minutes (or until the sound went away) and then came home and changed the oil and filter. It's worked flawlessly since.

FYI, when you do this, you'll want to drive around in a lower gear to keep your RPMs around 3500. That way the oil really gets flowing and can push out whatever crap is causing a blockage.


Good luck!

[ericem]

Perfect exactly what I wanted to hear!! I'm not suppost to usually drive in the 3500rpm range?

[asc_up]

Lol not if you're trying to be cost effective

But yeah, hope it works out for you. 3500 and then get on it, too. Maybe just floor it on an on ramp and give your car some highway miles in 3rd or 4th gear. That'll get the oil flowing.